/*
    madc.c
    Copyright (C) 2016  Pali Rohár <pali.rohar@gmail.com>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <stdio.h>
#include <stdlib.h>

#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>

#define TWL4030_MADC_PATH		"/dev/twl4030-adc"
#define TWL4030_MADC_IOC_MAGIC		'`'
#define TWL4030_MADC_IOCX_ADC_RAW_READ	_IO(TWL4030_MADC_IOC_MAGIC, 0)

struct twl4030_madc_user_parms {
	int channel;
	int average;
	int status;
	unsigned short int result;
};

int main(int argc, char *argv[]) {

	int fd;
	int ret;
	int channel;
	char *endptr;
	struct twl4030_madc_user_parms par;

	if (argc != 2) {
		fprintf(stderr, "Usage: %s channel\n", argv[0]);
		return 1;
	}

	channel = strtol(argv[1], &endptr, 10);
	if (channel < 0 || channel > 14 || *endptr != 0) {
		fprintf(stderr, "Incorrect channel number\n");
		return 1;
	}

	fd = open(TWL4030_MADC_PATH, O_RDONLY);
	if (fd < 0) {
		perror("Cannot open file " TWL4030_MADC_PATH);
		return 1;
	}

	par.channel = channel;
	par.average = 1;

	ret = ioctl(fd, TWL4030_MADC_IOCX_ADC_RAW_READ, &par);

	close(fd);

	if (ret != 0 || par.status != 0) {
		fprintf(stderr, "Reading %d channel failed\n", channel);
		return 1;
	}

	printf("Channel %d: %d\n", channel, par.result);
	return 0;

}